3.1. Example 1 - Datasets descriptions

3.1.1. Crowded with offset to sky

The data is a GSAOI observation of the resolved outskirt of a nearby galaxy. The observation is a dither-on-target with offset-to-sky sequence.

The table below contains a summary of the dataset downloaded in the previous section. Note that for GSAOI, the dark current is low enough that there is no need to correct for it.

The calibrations we use in this example are:

  • BPM. The bad pixel masks are now found in the Gemini Science Archive instead of being packaged with the software. They are associated like the other calibrations. Here we need the 2x2 binning GMOS-N Hamamatsu BPM valid for data taken in 2017. (The date in the name is the “valid from” date.)
  • Flats, as a sequence of lamps-on and lamps-off exposures.
  • A Standard star that could be used for photometry.


The Bad Pixel Masks (BPMs) are now found in the archive rather than packaged with the software. You must get the static BPM from the archive. See Getting Bad Pixel Masks from the archive in Tips and Tricks.

Kshort-band, on target, 60 s
Lamp on, Kshort, for science
Lamp off, Kshort, for science
Standard star
Kshort, standard star, 30 s